Two bib files in one latex file

I have two bib files and one latex file in a report style. I need one bibliography after my first part and the other bibliography at the end. Even though i got it somewhat correctly, the second bib files don't show the citations in the texts and instead shows like this: [?]. please help me fix this. I need to use bibtex compulsorily. Please help me. Thank you. My report outline looks like this:

\documentclass[12pt]{report}
\usepackage[margin=70pt]{geometry}
\usepackage{cite}
\usepackage{url}
\usepackage{etoolbox}
\apptocmd{\thebibliography}{\raggedright}{}{}
\title{aanfghn}
\author{Av}
\date{22 May 2017}

\begin{document}

\maketitle
\section{literature review}
some content here\cite{ref1}.
\bibliography{mybib1}
\bibliographystyle{plain}
\newpage
\section{Review of literature}
some content here[?].
\bibliography{mybib2}
\bibliographystyle{plain}


The first part cites the reference on pdf but the second part doesn't.

You can use the multibib package:

\documentclass{article}
\usepackage{multibib}
\newcites{first}{First Chapter Literature}
\newcites{second}{Second Chapter Literature}
\begin{document}
\nocitefirst{*}
\bibliographystylefirst{plain}
\bibliographyfirst{xampl}

\nocitesecond{*}
\bibliographystylesecond{plain}
\bibliographysecond{test}

\end{document}


You will then have to run bibtex first and bibtex second, e.g on a command line (my editor winedt does it automatically).